What do we want to know?

Are ‘comprehensive’ interventions more effective at reducing gang related criminal activity and anti-social behaviour than usual service provision?

We also want to know whether some types of comprehensive intervention are more effective than others.

Who wants to know and why?

Gang related crime and anti-social behaviour continue to be issues of concern at both a national and local level for communities, government at all levels and service delivery agencies. The review advisory group decided that the in-depth review should focus on ’comprehensive‘ interventions because:

social problems such as gangs are multi-dimensional in nature and cause;

these types of initiatives are consistent with current government policy which promotes multi-agency partnership working; and

the literature in this field suggests that multi-faceted approaches are more likely to be successful;

What did we find?

The meta-analysis of nine studies found that, overall, the comprehensive interventions had a positive, but not statistically significant, effect in reducing crime outcomes compared to usual service provision (i.e. whatever was in place either in a comparison area or before the specific intervention).

None of the studies included in the review considered the cost-benefit of any of the interventions. This kind of information is important to facilitate a more informed decision when choosing between different strategies. Any advantage of comprehensive interventions over non-comprehensive interventions may, for example, come at a greater financial cost.

The analysis also suggested that comprehensive interventions that included:

Case management/provision that was personalised to individual offenders

Community involvement in the planning of interventions

Community involvement in the delivery of interventions

Expertise shared between agencies

Delivery of incentives to gang members to change offending behaviour, as part of a wider comprehensive intervention approach; for example educational opportunities, tattoo removal, financial assistance, recreational activities

may be more effective than those that did not contain one or more of these components.

What are the implications?

The evidence is not strong enough to justify firm policy recommendations to use, or not use, comprehensive interventions as a means of tackling gang related criminal activity. The results, however, suggest a small positive effect in favour of comprehensive interventions which warrants further investigation.

The difficulties in evaluating gang prevention and reduction interventions are well documented and, perhaps unsurprisingly, this review found very few high quality evaluations of gang-related interventions. All of the interventions included in this review took place in the USA; therefore their transferability into a UK context would need careful management to ensure relevance and suitability. Comprehensive interventions certainly warrant further rigorous evaluation in a UK context and policy-makers should only support the use of such interventions in the context of a rigorous assessment.

The design of comprehensive interventions in a UK context should allow further investigation of those specific mechanisms of change which the analysis carried out and which suggest they are important for the design of successful comprehensive interventions.

How did we get these results?

A thorough search strategy was developed and all of the main social science databases were searched for relevant research. In addition, ‘handsearching’ of bibliographies and searches of the so-called ‘grey’ literature were undertaken. The initial searches identified 20,672 papers. From this group only seventeen studies evaluating this type of intervention were identified and synthesised to explore the relationships between the characteristics of the intervention; the types of outcomes reported; and the key mechanisms identified as driving changes in behaviour. Nine of the seventeen studies reported crime reduction or criminal justice related outcomes (e.g. crime rates, arrests and court appearances) which met the quality criteria for statistical synthesis. The results of these studies were pooled using meta-analysis.